BF: Was saving unwanted information in a TCK's header.

Author: MarcCote

nibabel/streamlines/tck.py

@@ -230,15 +230,15 @@ def _write_header(fileobj, header):
             from the beginning of the TCK header).
         """
         # Fields to exclude
-        exclude = [Field.MAGIC_NUMBER, Field.NB_STREAMLINES,
-                   "datatype", "file"]
+        exclude = [Field.MAGIC_NUMBER, Field.NB_STREAMLINES, Field.ENDIANNESS,
+                   "count", "datatype", "file"]
 
         lines = []
         lines.append(header[Field.MAGIC_NUMBER])
         lines.append("count: {0:010}".format(header[Field.NB_STREAMLINES]))
         lines.append("datatype: Float32LE")  # Always Float32LE.
         lines.extend(["{0}: {1}".format(k, v)
-                      for k, v in header.items() if k not in exclude])
+                      for k, v in header.items() if k not in exclude and not k.startswith("_")])
         lines.append("file: . ")  # Manually add this last field.
         out = "\n".join((asstr(line).replace('\n', '\t') for line in lines))
         fileobj.write(asbytes(out))
@@ -281,7 +281,7 @@ def _read_header(fileobj):
 
         with Opener(fileobj) as f:
             # Read magic number
-            magic_number = asstr(f.fobj.readline())
+            magic_number = asstr(f.fobj.readline()).strip()
 
             # Read all key-value pairs contained in the header.
             buf = asstr(f.fobj.readline())

nibabel/streamlines/tests/test_tck.py

@@ -162,14 +162,18 @@ def test_load_write_file(self):
                 loaded_tck = TckFile.load(fname, lazy_load=False)
                 assert_tractogram_equal(loaded_tck.tractogram, tck.tractogram)
 
+                # Check that the written file is the same as the one read.
+                tck_file.seek(0, os.SEEK_SET)
+                assert_equal(tck_file.read(), open(fname, 'rb').read())
+
         # Save tractogram that has an affine_to_rasmm.
         for lazy_load in [False, True]:
             tck = TckFile.load(DATA['simple_tck_fname'], lazy_load=lazy_load)
             affine = np.eye(4)
             affine[0, 0] *= -1  # Flip in X
             tractogram = Tractogram(tck.streamlines, affine_to_rasmm=affine)
 
-            new_tck = TckFile(tractogram)
+            new_tck = TckFile(tractogram, tck.header)
             tck_file = BytesIO()
             new_tck.save(tck_file)
             tck_file.seek(0, os.SEEK_SET)